Molecular characterisation of methicillin-resistant Staphylococcus aureus from chronically colonised cystic fibrosis paediatric patients in Brazil

Abstract

Persistent methicillin-resistant Staphylococcus aureus (MRSA) infection in cystic fibrosis (CF) patients has been associated with a more rapid decline in lung function, increased hospitalisation and mortality. The aim of this study was to evaluate the clonal relationships among 116 MRSA isolates from 12 chronically colonised CF pediatric patients over a 6-year period in a Rio de Janeiro CF specialist centre. Isolates were characterised by antimicrobial resistance, SCCmec type, presence of Panton-Valentine Leukocidin (PVL) genes and grouped according to DNA macrorestriction profile by pulsed-field gel electrophoresis (PFGE) and spa gene type. High resistance rates were detected for erythromycin (78%) and ciprofloxacin (50%) and SCCmec IV was the most common type (72.4%). Only 8.6% of isolates were PVL positive. High genetic diversity was evident by PFGE (39 pulsotypes) and of nine that were identified spa types, t002 (53.1%) and t539 (14.8%) were the most prevalent. We conclude that the observed homogeneity of spa types within patients over the study period demonstrates the persistence of such strain lineages throughout the course of chronic lung infection.

Virulence Factors Found in Nasal Colonization and Infection of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates and Their Ability to Form a Biofilm

“…Comparing the antimicrobial resistance burden found herein, with other studies conducted in different regions in our country, both colonization and invasive infection isolates seem to present a similar antimicrobial resistance profile. Studies conducted in the southern Brazilian region, such as Santa Catarina [37], the northern region, such as Piauí [38], Bahia [39], and Paraíba [40], and the southeastern region [2,3] with invasive infection and colonization isolates, present antimicrobial resistance profiles similar to ours. These isolates present mainly resistance to erythromycin, clindamycin, and ciprofloxacin.…”

“…These isolates present mainly resistance to erythromycin, clindamycin, and ciprofloxacin. Although similar patterns of antimicrobial resistance are observed, the resistance frequency among the isolates in relation to tetracycline (8.06% in invasive infections and 4.7% in colonization), for example, presents a lower frequency when compared to others studies conducted in our region and other regions of Brazil [2,3,37,38,40]. Thus, showing that regional characteristics such as measures for the control and treatment of MRSA infections can influence the particularities found in circulating strains, reinforcing the need for active surveillance of circulating strains and the treatment procedure must be tailored based on the specific region of Brazil.…”

“…More than 30% of the healthy population is colonized by Staphylococcus aureus , making these subjects vehicles of dissemination of this pathogen [ 1 ]. For the past few years, studies conducted in Brazil have shown an increased number of colonizing Methicillin-resistant S. aureus (MRSA) isolates, in different age groups and with a marked antimicrobial resistance profile, pointing to the importance of monitoring this pathogen frequency and its particular characteristics, such as antimicrobial resistance patterns [ 2 , 3 , 4 , 5 , 6 ]. A high degree of similarity between nasal colonization and invasive infection isolates collected from the same patient has already been demonstrated [ 7 , 8 , 9 ], reinforcing the importance of detecting the presence of the nasal colonization and particular characteristics that could be responsible for this pathogen success and future infection development.…”

“…An increasing number of MRSA strains are circulating in different hospitals and communities in Brazil, as well as worldwide [ 22 , 23 , 24 , 25 , 26 ]. Although the Brazilian Epidemic Clone (BEC) (ST239 SCC mec III) remains circulating in different hospitals and the community in our country [ 27 , 28 ], previous studies have shown the substitution of this clone for others, such as the New York/Japan clone (USA100/ST5/CC5/SCCmecII), community-acquired MRSA (USA300/ST8/CC8/SCCmecIV), and pediatric clone (USA800/ST5/CC5/SCCmecIV) [ 2 , 3 , 4 , 29 ]. This fact has evidenced the need for studies on the epidemiological, microbiological, and genetic characteristics of these microorganisms to improve and better understand the pathogen evolution, the scenario changes, and update control measures.…”

Distribution and Characteristics of Bacteria Isolated from Cystic Fibrosis Patients with Pulmonary Exacerbation

“…Analysis of rep-PCR results indicate that the majority of our patients are infected with different lineages ( Figure 3(d) and supplementary Table 3 ). The great diversity may be associated with microevolutionary events in the airway environment of CF patients [ 50 ]. The surveillance of the different morphotypes of P. aeruginosa isolated from individual CF patients to recognize when new morphotypes that may be more resistant to antimicrobial agents emerge is of great concern.…”